Certain isothermal amplification methods are able to amplify a target nucleic acid from trace levels to very high and detectable levels within a matter of minutes. Such isothermal methods, e.g., Nicking and Extension Amplification Reaction (NEAR), allow users to detect a particular nucleotide sequence in trace amounts, facilitating point-of-care testing and increasing the accessibility and speed of diagnostics.
Streptococcus pyogenes is the causative agent of group A streptococcal (GAS) infections such as pharyngitis, impetigo, and life-threatening necrotizing fasciitis and sepsis. The most common GAS infection, pharyngitis, can be diagnosed by collecting a throat swab sample from a patient and culturing the sample under conditions that would enable bacterial, specifically S. pyogenes, growth, which takes 2-3 days. Culturing S. pyogenes is an accurate and reliable method of diagnosing GAS, but it is slow. A 2-3 day delay in prescribing appropriate antibiotic treatment can result in unnecessary patient suffering and potentially the onset of life threatening conditions such as rheumatic fever. In the recent past, biochemical methods have been developed to detect S. pyogenes, but these methods do not provide the necessary characteristics to be deployed in the point-of-care setting, either due to a lack of sensitivity or time to result (speed).
Accordingly, a highly sensitive and rapid qualitative assay for the detection and diagnosis of a S. pyogenes infection is desired.